Fix a type inference corner case: return expression where void expected.

pkg/front_end/testcases/inference/block_bodied_lambdas_void_context.dart.direct.expect

Index: pkg/front_end/testcases/inference/block_bodied_lambdas_void_context.dart.direct.expect
diff --git a/pkg/front_end/testcases/inference/block_bodied_lambdas_void_context.dart.direct.expect b/pkg/front_end/testcases/inference/block_bodied_lambdas_void_context.dart.direct.expect
new file mode 100644
index 0000000000000000000000000000000000000000..42730831a76acf890af37a8b33c012672554050a
--- /dev/null
+++ b/pkg/front_end/testcases/inference/block_bodied_lambdas_void_context.dart.direct.expect
@@ -0,0 +1,11 @@
+library test;
+import self as self;
+import "dart:core" as core;
+
+static method f() → dynamic {
+  core::List<core::int> o;
+  o.forEach((dynamic i) → dynamic {
+    return i.+(1);
+  });
+}
+static method main() → dynamic {}